This is a testimonial of the Cyanogenmod 7.1 Android spinoff operating system on the ZTE Blade phone.
I've recently installed Cyanogenmod 7.1 to my ZTE Blade. Prevously I had Cyanogenmod 7.0.3 on it, and the battery life was terrible. It didn't last more than 48 hours in standby (3G, mobile data, wifi, GPS, background synchronization switched off, only receiving a few text messages). But after installing 7.1, the battery lasted for 12 days plus 23 hours in standby mode. Awesome! Finally I have a small and cheap Android phone with long battery life.
The phone user interface also feels much snappier now, and 3D games (e.g. Falldown 3D) which lagged and were unplayable with 7.0.3 are fast and playable now.
Unfortunately I wasn't able to upgrade 7.0.3 to 7.1, but I had to wipe the phone (keeping only the SD card contents) before installing 7.1.